Re: Simplification question
- To: mathgroup at smc.vnet.net
- Subject: [mg110424] Re: Simplification question
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Thu, 17 Jun 2010 02:05:16 -0400 (EDT)
(TrigToExp[ArcTanh[Tanh[a] Tanh[b]]] == 1/2 Log[(Exp[a+b]+Exp[-a-b])/(Exp[-a+b]+Exp[a-b])]) //Simplify[#,Assumptions->{a\[Element]Reals,b\[Element]Reals}]& True On 6/15/2010 2:30 AM, Yaroslav Bulatov wrote: > I'd like to verify that the following expression is true for a,b real. > It seems to hold numerically. > > 1/2 Log[(Exp[a + b] + Exp[-a - b])/(Exp[-a + b] + Exp[a - b])] == > ArcTanh[Tanh[a] Tanh[b]] > > I tried Reduce and combinations of TrigToExp/Simplify with no luck, > any suggestions? > -- Murray Eisenberg murrayeisenberg at gmail.com 80 Fearing Street phone 413 549-1020 (H) Amherst, MA 01002-1912